overheating M50 - help!

[Ziggens96]

I had a radiator hose come loose on the Palisades Parkway in Alpine, NJ this afternoon in my M50'd 318is. Car was overheating so I pulled over, got the hose re-attached with a new clamp, let it cool down, and then filled the car up with coolant. Now it continues to overheat and I am not getting any cabin heat. I had some bubbles in the expansion tank and was afraid it was a head gasket failure, but the car was only gently driven for a minute or two after the coolant temp started rising on the highway until I could exit off the highway (no shoulder). I am hoping the bubbles were just trapped air in the cooling system escaping.

With all that said, I think the problem is a stuck thermostat.

Maybe there is just still air stuck in the system? I am not really sure if I was bleeding the system correctly...I ran it with the cabin heat on full hot for a while, with the expansion tank cap off and kept adding coolant...but my temp needle kept going up. What does this sound like the problem is? T-stat?

[MaksV]

and you still need to bleed the system.

[Danny]

Bleed the system, obv.

[Ziggens96]

thanks guys...I'll see if I can get it bled properly tomorrow morning before I get a tow truck. I get free tows through my insurance's roadside assistance so it's not a big deal if I have to do that. But obviously it would be better if I can just get it running right myself.

copying and pasting this from E30tech, maybe this will be helpful:

"Makes sense...I don't know what I'm doing wrong though. I have my Bentley manual so I'm going to read the entire cooling section tonight.

I've read several bleeding procedures before on the internet, and I've successfully bled the system more than once on my stock 318is.

Why do I have no cabin heat though? The air in the system is preventing the coolant from going into the engine causing no heat and causing the engine to overheat?

I had the car jacked up on the driver's side and I ran the cabin heat on full hot while I slowly added coolant, keeping it right at the middle mark. The coolant level stopped going down, so then I ran the engine with the radiator car off... when the engine got hot, the coolant started rising up and when it started overflowing I put the cap on. Then I unscrewed the bleeder valve to release the pressure, and only air came out, for a long time. Coolant level in expansion tank remained high, but still only air came out of the bleeder.

What am I doing wrong?

Thanks for your help, it's much appreciated."

please excuse the noobish questions BTW.

[Ziggens96]

Or...are the symptoms of having air stuck in the lines the exact same as having a stuck thermostat?

[Ziggens96]

It was the thermostat.